DNTH

SEC source: 0000899243-18-018342 · doc4.xml · nonDerivative · entry 1

Atlas Venture Fund X, L.P. · CIK 0001628098 · 10% owner

ATLAS VENTURE ASSOCIATES X, L.P. · CIK 0001742766 · 10% owner

Atlas Venture Associates X, LLC · CIK 0001742765 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 4,843,625

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F2 · ownership.direct: The shares are held directly by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. Each of AVA X LP and AVA X LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund X, except to the extent of its pecuniary interest therein, if any.

SEC source: 0000899243-18-018339 · doc4.xml · derivative · entry 3

Third Rock Ventures IV, L.P. · CIK 0001688327 · 10% owner

Third Rock Ventures GP IV, L.P. · CIK 0001688326 · 10% owner

TRV GP IV, LLC · CIK 0001688325 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 131,799 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F2 · ownership.direct: The shares are directly held by Third Rock Ventures IV, L.P. ("TRV IV"). The general partner of TRV IV is Third Rock Ventures GP IV, L.P. ("TRV GP IV"). The general partner of TRV GP IV is TRV GP IV, LLC ("TRV GP IV LLC"). Each of TRV GP IV and TRV GP IV LLC disclaims beneficial ownership of these shares except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that it is the beneficial owner of such shares.

SEC source: 0000899243-18-018339 · doc4.xml · derivative · entry 2

Third Rock Ventures IV, L.P. · CIK 0001688327 · 10% owner

Third Rock Ventures GP IV, L.P. · CIK 0001688326 · 10% owner

TRV GP IV, LLC · CIK 0001688325 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 7,779,656 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F2 · ownership.direct: The shares are directly held by Third Rock Ventures IV, L.P. ("TRV IV"). The general partner of TRV IV is Third Rock Ventures GP IV, L.P. ("TRV GP IV"). The general partner of TRV GP IV is TRV GP IV, LLC ("TRV GP IV LLC"). Each of TRV GP IV and TRV GP IV LLC disclaims beneficial ownership of these shares except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that it is the beneficial owner of such shares.

SEC source: 0000899243-18-018339 · doc4.xml · nonDerivative · entry 1

Third Rock Ventures IV, L.P. · CIK 0001688327 · 10% owner

Third Rock Ventures GP IV, L.P. · CIK 0001688326 · 10% owner

TRV GP IV, LLC · CIK 0001688325 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 8,008,204

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F2 · ownership.direct: The shares are directly held by Third Rock Ventures IV, L.P. ("TRV IV"). The general partner of TRV IV is Third Rock Ventures GP IV, L.P. ("TRV GP IV"). The general partner of TRV GP IV is TRV GP IV, LLC ("TRV GP IV LLC"). Each of TRV GP IV and TRV GP IV LLC disclaims beneficial ownership of these shares except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that it is the beneficial owner of such shares.

SEC source: 0000899243-18-018338 · doc4.xml · derivative · entry 3

Daniel Thomas O · CIK 0001538894 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 11,620 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018338 · doc4.xml · derivative · entry 2

Daniel Thomas O · CIK 0001538894 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 12,907 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018338 · doc4.xml · nonDerivative · entry 1

Daniel Thomas O · CIK 0001538894 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 101,926

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018334 · doc4.xml · derivative · entry 3

RONNEBERG AMY L · CIK 0001380292 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 95,504 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F2 · ownership.direct: The shares are held directly by Be The Match BioTherapies, LLC ("Be the Match"). Ms. Ronneberg is President of Be The Match and disclaims beneficial ownership of such securities, except to the extent of her pecuniary interest therein, if any.

F2 · ownership.nature: The shares are held directly by Be The Match BioTherapies, LLC ("Be the Match"). Ms. Ronneberg is President of Be The Match and disclaims beneficial ownership of such securities, except to the extent of her pecuniary interest therein, if any.

SEC source: 0000899243-18-018334 · doc4.xml · derivative · entry 2

RONNEBERG AMY L · CIK 0001380292 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 498,107 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F2 · ownership.direct: The shares are held directly by Be The Match BioTherapies, LLC ("Be the Match"). Ms. Ronneberg is President of Be The Match and disclaims beneficial ownership of such securities, except to the extent of her pecuniary interest therein, if any.

F2 · ownership.nature: The shares are held directly by Be The Match BioTherapies, LLC ("Be the Match"). Ms. Ronneberg is President of Be The Match and disclaims beneficial ownership of such securities, except to the extent of her pecuniary interest therein, if any.

SEC source: 0000899243-18-018334 · doc4.xml · nonDerivative · entry 1

RONNEBERG AMY L · CIK 0001380292 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 593,611

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: The Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F2 · ownership.direct: The shares are held directly by Be The Match BioTherapies, LLC ("Be the Match"). Ms. Ronneberg is President of Be The Match and disclaims beneficial ownership of such securities, except to the extent of her pecuniary interest therein, if any.

F2 · ownership.nature: The shares are held directly by Be The Match BioTherapies, LLC ("Be the Match"). Ms. Ronneberg is President of Be The Match and disclaims beneficial ownership of such securities, except to the extent of her pecuniary interest therein, if any.

SEC source: 0000899243-18-018333 · doc4.xml · derivative · entry 3

COOKE MICHAEL P. · CIK 0001741288 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 498 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018333 · doc4.xml · derivative · entry 2

COOKE MICHAEL P. · CIK 0001741288 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 3,872 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018333 · doc4.xml · nonDerivative · entry 1

COOKE MICHAEL P. · CIK 0001741288 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 293,023

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018332 · doc4.xml · derivative · entry 2

ZDRAVESKI ZORAN · CIK 0001741285 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 4,643 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series C Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Series C Preferred Stock had no expiration date.

F1 · price: The Series C Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Series C Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series C Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Series C Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series C Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Series C Preferred Stock had no expiration date.

SEC source: 0000899243-18-018332 · doc4.xml · nonDerivative · entry 1

ZDRAVESKI ZORAN · CIK 0001741285 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 140,092

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: The Series C Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Series C Preferred Stock had no expiration date.

SEC source: 0000899243-18-018328 · doc4.xml · derivative · entry 3

Booth Bruce · CIK 0001451612 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 79,079 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F2 · ownership.direct: The shares are held directly by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. Dr. Booth is a member of AVA X LLC and disclaims beneficial ownership of such securities held by Atlas Venture Fund X, except to the extent of his pecuniary interest therein, if any.

F2 · ownership.nature: The shares are held directly by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. Dr. Booth is a member of AVA X LLC and disclaims beneficial ownership of such securities held by Atlas Venture Fund X, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-18-018328 · doc4.xml · derivative · entry 2

Booth Bruce · CIK 0001451612 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 4,667,797 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F2 · ownership.direct: The shares are held directly by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. Dr. Booth is a member of AVA X LLC and disclaims beneficial ownership of such securities held by Atlas Venture Fund X, except to the extent of his pecuniary interest therein, if any.

F2 · ownership.nature: The shares are held directly by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. Dr. Booth is a member of AVA X LLC and disclaims beneficial ownership of such securities held by Atlas Venture Fund X, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-18-018328 · doc4.xml · nonDerivative · entry 1

Booth Bruce · CIK 0001451612 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 4,843,625

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F2 · ownership.direct: The shares are held directly by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. Dr. Booth is a member of AVA X LLC and disclaims beneficial ownership of such securities held by Atlas Venture Fund X, except to the extent of his pecuniary interest therein, if any.

F2 · ownership.nature: The shares are held directly by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. Dr. Booth is a member of AVA X LLC and disclaims beneficial ownership of such securities held by Atlas Venture Fund X, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-18-018325 · doc4.xml · derivative · entry 3

BONNEY MICHAEL W · CIK 0001219016 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 2,488 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018325 · doc4.xml · derivative · entry 2

BONNEY MICHAEL W · CIK 0001219016 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 19,359 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018325 · doc4.xml · nonDerivative · entry 1

BONNEY MICHAEL W · CIK 0001219016 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 215,346

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: The Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018323 · doc4.xml · derivative · entry 2

Albers Jeffrey W. · CIK 0001638474 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 4,152 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series C Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Series C Preferred Stock had no expiration date.

F1 · price: The Series C Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Series C Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series C Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Series C Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series C Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Series C Preferred Stock had no expiration date.

SEC source: 0000899243-18-018323 · doc4.xml · nonDerivative · entry 1

Albers Jeffrey W. · CIK 0001638474 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 4,152

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: The Series C Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Series C Preferred Stock had no expiration date.

SEC source: 0000899243-18-018319 · doc4.xml · derivative · entry 3

BYERS BLAKE · CIK 0001741840 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 3,287,511 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public without payment of further consideration. The shares had no expiration date.

F1 · price: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public without payment of further consideration. The shares had no expiration date.

F1 · derivative.exercise_date: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public without payment of further consideration. The shares had no expiration date.

F1 · derivative.expiration_date: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public without payment of further consideration. The shares had no expiration date.

F2 · ownership.direct: The reported securities are directly held by GV 2016, L.P. GV 2016 GP, L.P., the general partner of GV 2016, L.P., GV 2016 GP, L.L.C., the general partner of GV 2016 GP, L.P., Alphabet Holdings LLC, the sole member of GV 2016 GP, L.L.C., XXVI Holdings Inc., the managing member of Alphabet Holdings LLC, and Alphabet Inc., the sole stockholder of XXVI Holdings Inc., may each be deemed to have sole power to vote or dispose of these shares. Dr. Byers is an affiliate of GV 2016 GP, L.P. but does not have voting or dispositive power over the shares held by GV 2016, L.P. Dr. Byers disclaims beneficial ownership of the shares held by GV 2016, L.P. except to the extent of his pecuniary interest, if any, therein and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of the reported securities for the purpose of Section 16 or for any other purpose.

F2 · ownership.nature: The reported securities are directly held by GV 2016, L.P. GV 2016 GP, L.P., the general partner of GV 2016, L.P., GV 2016 GP, L.L.C., the general partner of GV 2016 GP, L.P., Alphabet Holdings LLC, the sole member of GV 2016 GP, L.L.C., XXVI Holdings Inc., the managing member of Alphabet Holdings LLC, and Alphabet Inc., the sole stockholder of XXVI Holdings Inc., may each be deemed to have sole power to vote or dispose of these shares. Dr. Byers is an affiliate of GV 2016 GP, L.P. but does not have voting or dispositive power over the shares held by GV 2016, L.P. Dr. Byers disclaims beneficial ownership of the shares held by GV 2016, L.P. except to the extent of his pecuniary interest, if any, therein and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of the reported securities for the purpose of Section 16 or for any other purpose.

SEC source: 0000899243-18-018319 · doc4.xml · derivative · entry 2

BYERS BLAKE · CIK 0001741840 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 51,626 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public without payment of further consideration. The shares had no expiration date.

F1 · price: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public without payment of further consideration. The shares had no expiration date.

F1 · derivative.exercise_date: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public without payment of further consideration. The shares had no expiration date.

F1 · derivative.expiration_date: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public without payment of further consideration. The shares had no expiration date.

F2 · ownership.direct: The reported securities are directly held by GV 2016, L.P. GV 2016 GP, L.P., the general partner of GV 2016, L.P., GV 2016 GP, L.L.C., the general partner of GV 2016 GP, L.P., Alphabet Holdings LLC, the sole member of GV 2016 GP, L.L.C., XXVI Holdings Inc., the managing member of Alphabet Holdings LLC, and Alphabet Inc., the sole stockholder of XXVI Holdings Inc., may each be deemed to have sole power to vote or dispose of these shares. Dr. Byers is an affiliate of GV 2016 GP, L.P. but does not have voting or dispositive power over the shares held by GV 2016, L.P. Dr. Byers disclaims beneficial ownership of the shares held by GV 2016, L.P. except to the extent of his pecuniary interest, if any, therein and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of the reported securities for the purpose of Section 16 or for any other purpose.

F2 · ownership.nature: The reported securities are directly held by GV 2016, L.P. GV 2016 GP, L.P., the general partner of GV 2016, L.P., GV 2016 GP, L.L.C., the general partner of GV 2016 GP, L.P., Alphabet Holdings LLC, the sole member of GV 2016 GP, L.L.C., XXVI Holdings Inc., the managing member of Alphabet Holdings LLC, and Alphabet Inc., the sole stockholder of XXVI Holdings Inc., may each be deemed to have sole power to vote or dispose of these shares. Dr. Byers is an affiliate of GV 2016 GP, L.P. but does not have voting or dispositive power over the shares held by GV 2016, L.P. Dr. Byers disclaims beneficial ownership of the shares held by GV 2016, L.P. except to the extent of his pecuniary interest, if any, therein and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of the reported securities for the purpose of Section 16 or for any other purpose.

SEC source: 0000899243-18-018319 · doc4.xml · nonDerivative · entry 1

BYERS BLAKE · CIK 0001741840 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 3,339,137

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public without payment of further consideration. The shares had no expiration date.

F2 · ownership.direct: The reported securities are directly held by GV 2016, L.P. GV 2016 GP, L.P., the general partner of GV 2016, L.P., GV 2016 GP, L.L.C., the general partner of GV 2016 GP, L.P., Alphabet Holdings LLC, the sole member of GV 2016 GP, L.L.C., XXVI Holdings Inc., the managing member of Alphabet Holdings LLC, and Alphabet Inc., the sole stockholder of XXVI Holdings Inc., may each be deemed to have sole power to vote or dispose of these shares. Dr. Byers is an affiliate of GV 2016 GP, L.P. but does not have voting or dispositive power over the shares held by GV 2016, L.P. Dr. Byers disclaims beneficial ownership of the shares held by GV 2016, L.P. except to the extent of his pecuniary interest, if any, therein and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of the reported securities for the purpose of Section 16 or for any other purpose.

F2 · ownership.nature: The reported securities are directly held by GV 2016, L.P. GV 2016 GP, L.P., the general partner of GV 2016, L.P., GV 2016 GP, L.L.C., the general partner of GV 2016 GP, L.P., Alphabet Holdings LLC, the sole member of GV 2016 GP, L.L.C., XXVI Holdings Inc., the managing member of Alphabet Holdings LLC, and Alphabet Inc., the sole stockholder of XXVI Holdings Inc., may each be deemed to have sole power to vote or dispose of these shares. Dr. Byers is an affiliate of GV 2016 GP, L.P. but does not have voting or dispositive power over the shares held by GV 2016, L.P. Dr. Byers disclaims beneficial ownership of the shares held by GV 2016, L.P. except to the extent of his pecuniary interest, if any, therein and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of the reported securities for the purpose of Section 16 or for any other purpose.

SEC source: 0000899243-18-018317 · doc4.xml · derivative · entry 2

DAVIS JOHN C. JR · CIK 0001741287 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 8,304 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series C Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Series C Preferred Stock had no expiration date.

F1 · price: The Series C Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Series C Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series C Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Series C Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series C Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Series C Preferred Stock had no expiration date.

SEC source: 0000899243-18-018317 · doc4.xml · nonDerivative · entry 1

DAVIS JOHN C. JR · CIK 0001741287 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 8,304

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: The Series C Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Series C Preferred Stock had no expiration date.

SEC source: 0000899243-18-018315 · doc4.xml · derivative · entry 3

Borisy Alexis · CIK 0001319446 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 0 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: The Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F4 · shares: Prior to the conversion, the Fund held 20,102,478 shares of Series A Preferred Stock and 340,566 shares of Series B Preferred Stock.

F2 · price: The Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F2 · derivative.exercise_date: The Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F2 · derivative.expiration_date: The Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F5 · derivative.underlying_shares: Prior to the conversion, the shares of Common Stock underlying the Series A Preferred Stock and Series B Preferred Stock held by the Fund were 7,779,656 and 131,799, respectively.

F3 · ownership.nature: The Reporting Person is a partner of Third Rock Ventures GP IV, L.P., which is the general partner of the Fund. The reporting person disclaims beneficial ownership over the shares held by the Fund, except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that he is the beneficial owner of such shares.

SEC source: 0000899243-18-018315 · doc4.xml · derivative · entry 2

Borisy Alexis · CIK 0001319446 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 0 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · derivative.exercise_price: The Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F4 · shares: Prior to the conversion, the Fund held 20,102,478 shares of Series A Preferred Stock and 340,566 shares of Series B Preferred Stock.

F2 · price: The Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F2 · derivative.exercise_date: The Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F2 · derivative.expiration_date: The Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F5 · derivative.underlying_shares: Prior to the conversion, the shares of Common Stock underlying the Series A Preferred Stock and Series B Preferred Stock held by the Fund were 7,779,656 and 131,799, respectively.

F3 · ownership.nature: The Reporting Person is a partner of Third Rock Ventures GP IV, L.P., which is the general partner of the Fund. The reporting person disclaims beneficial ownership over the shares held by the Fund, except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that he is the beneficial owner of such shares.

SEC source: 0000899243-18-018315 · doc4.xml · nonDerivative · entry 1

Borisy Alexis · CIK 0001319446 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · shares: Represents 7,911,455 shares held by Third Rock Ventures IV, L.P. (the "Fund") received by the Fund upon conversion of Series A Preferred Stock and Series B Preferred Stock (collectively, the "Preferred Stock") upon closing of the Issuer's initial public offering on June 25, 2018.

F2 · price: The Preferred Stock converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F3 · ownership.nature: The Reporting Person is a partner of Third Rock Ventures GP IV, L.P., which is the general partner of the Fund. The reporting person disclaims beneficial ownership over the shares held by the Fund, except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that he is the beneficial owner of such shares.

SEC source: 0000899243-18-018316 · doc4.xml · derivative · entry 8

GARDNER JASON · CIK 0001741286 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Indirect · By J.P. Gardner Irrevocable Trust

Disclosed balance after: 0

Underlying: Common Stock · 8,304 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · ownership.direct: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018316 · doc4.xml · derivative · entry 7

GARDNER JASON · CIK 0001741286 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Indirect · By P.S. Gardner Irrevocable Trust

Disclosed balance after: 0

Underlying: Common Stock · 7,474 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · ownership.direct: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018316 · doc4.xml · derivative · entry 6

GARDNER JASON · CIK 0001741286 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Indirect · By J.P. Gardner Irrevocable Trust

Disclosed balance after: 0

Underlying: Common Stock · 5,804 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · ownership.direct: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018316 · doc4.xml · derivative · entry 5

GARDNER JASON · CIK 0001741286 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Indirect · By P.S. Gardner Irrevocable Trust

Disclosed balance after: 0

Underlying: Common Stock · 14,203 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · ownership.direct: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018316 · doc4.xml · derivative · entry 4

GARDNER JASON · CIK 0001741286 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Indirect · By J.P. Gardner Irrevocable Trust

Disclosed balance after: 0

Underlying: Common Stock · 11,611 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · price: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

F1 · ownership.direct: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018316 · doc4.xml · nonDerivative · entry 3

GARDNER JASON · CIK 0001741286 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 363,212

F2 · shares: Reflects shares that were purchased through a directed share program in connection with the Issuer's initial public offering.

SEC source: 0000899243-18-018316 · doc4.xml · nonDerivative · entry 2

GARDNER JASON · CIK 0001741286 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Indirect · By P.S. Gardner Irrevocable Trust

Disclosed balance after: 359,092

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018316 · doc4.xml · nonDerivative · entry 1

GARDNER JASON · CIK 0001741286 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Indirect · By J.P. Gardner Irrevocable Trust

Disclosed balance after: 292,990

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: The Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the "Preferred Stock") converted into Common Stock on a 2.58398:1 basis upon the closing of the Issuer's initial public offering on June 25, 2018. The Preferred Stock had no expiration date.

SEC source: 0000899243-18-018327 · doc4.xml · derivative · entry 3

GV 2016 GP, L.L.C. · CIK 0001722201 · 10% owner

GV 2016 GP, L.P. · CIK 0001722204 · 10% owner

GV 2016, L.P. · CIK 0001721789 · 10% owner

Alphabet Inc. · CIK 0001652044 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By GV 2016, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 3,287,511 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public offering without payment of further consideration. The shares had no expiration date.

F1 · price: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public offering without payment of further consideration. The shares had no expiration date.

F1 · derivative.exercise_date: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public offering without payment of further consideration. The shares had no expiration date.

F1 · derivative.expiration_date: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public offering without payment of further consideration. The shares had no expiration date.

F2 · ownership.direct: The reported securities are directly held by GV 2016, L.P. GV 2016 GP, L.P., the general partner of GV 2016, L.P., GV 2016 GP, L.L.C., the general partner of GV 2016 GP, L.P., Alphabet Holdings LLC, the sole member of GV 2016 GP, L.L.C., XXVI Holdings Inc., the managing member of Alphabet Holdings LLC, and Alphabet Inc., the sole stockholder of XXVI Holdings Inc., may each be deemed to have sole power to vote or dispose of these shares. Each of GV 2016 GP, L.P., GV 2016 GP, L.L.C., Alphabet Holdings LLC, XXVI Holdings Inc. and Alphabet Inc. disclaim beneficial ownership of the shares except to the extent of any pecuniary interest therein.

F2 · ownership.nature: The reported securities are directly held by GV 2016, L.P. GV 2016 GP, L.P., the general partner of GV 2016, L.P., GV 2016 GP, L.L.C., the general partner of GV 2016 GP, L.P., Alphabet Holdings LLC, the sole member of GV 2016 GP, L.L.C., XXVI Holdings Inc., the managing member of Alphabet Holdings LLC, and Alphabet Inc., the sole stockholder of XXVI Holdings Inc., may each be deemed to have sole power to vote or dispose of these shares. Each of GV 2016 GP, L.P., GV 2016 GP, L.L.C., Alphabet Holdings LLC, XXVI Holdings Inc. and Alphabet Inc. disclaim beneficial ownership of the shares except to the extent of any pecuniary interest therein.

SEC source: 0000899243-18-018327 · doc4.xml · derivative · entry 2

GV 2016 GP, L.L.C. · CIK 0001722201 · 10% owner

GV 2016 GP, L.P. · CIK 0001722204 · 10% owner

GV 2016, L.P. · CIK 0001721789 · 10% owner

Alphabet Inc. · CIK 0001652044 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By GV 2016, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 51,626 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public offering without payment of further consideration. The shares had no expiration date.

F1 · price: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public offering without payment of further consideration. The shares had no expiration date.

F1 · derivative.exercise_date: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public offering without payment of further consideration. The shares had no expiration date.

F1 · derivative.expiration_date: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public offering without payment of further consideration. The shares had no expiration date.

F2 · ownership.direct: The reported securities are directly held by GV 2016, L.P. GV 2016 GP, L.P., the general partner of GV 2016, L.P., GV 2016 GP, L.L.C., the general partner of GV 2016 GP, L.P., Alphabet Holdings LLC, the sole member of GV 2016 GP, L.L.C., XXVI Holdings Inc., the managing member of Alphabet Holdings LLC, and Alphabet Inc., the sole stockholder of XXVI Holdings Inc., may each be deemed to have sole power to vote or dispose of these shares. Each of GV 2016 GP, L.P., GV 2016 GP, L.L.C., Alphabet Holdings LLC, XXVI Holdings Inc. and Alphabet Inc. disclaim beneficial ownership of the shares except to the extent of any pecuniary interest therein.

F2 · ownership.nature: The reported securities are directly held by GV 2016, L.P. GV 2016 GP, L.P., the general partner of GV 2016, L.P., GV 2016 GP, L.L.C., the general partner of GV 2016 GP, L.P., Alphabet Holdings LLC, the sole member of GV 2016 GP, L.L.C., XXVI Holdings Inc., the managing member of Alphabet Holdings LLC, and Alphabet Inc., the sole stockholder of XXVI Holdings Inc., may each be deemed to have sole power to vote or dispose of these shares. Each of GV 2016 GP, L.P., GV 2016 GP, L.L.C., Alphabet Holdings LLC, XXVI Holdings Inc. and Alphabet Inc. disclaim beneficial ownership of the shares except to the extent of any pecuniary interest therein.

SEC source: 0000899243-18-018327 · doc4.xml · nonDerivative · entry 1

GV 2016 GP, L.L.C. · CIK 0001722201 · 10% owner

GV 2016 GP, L.P. · CIK 0001722204 · 10% owner

GV 2016, L.P. · CIK 0001721789 · 10% owner

Alphabet Inc. · CIK 0001652044 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · By GV 2016, L.P.

Disclosed balance after: 3,339,137

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: The reported securities converted into shares of the Issuer's common stock on a 2.58398:1 basis automatically immediately prior to the closing of the Issuer's initial public offering without payment of further consideration. The shares had no expiration date.

F2 · ownership.direct: The reported securities are directly held by GV 2016, L.P. GV 2016 GP, L.P., the general partner of GV 2016, L.P., GV 2016 GP, L.L.C., the general partner of GV 2016 GP, L.P., Alphabet Holdings LLC, the sole member of GV 2016 GP, L.L.C., XXVI Holdings Inc., the managing member of Alphabet Holdings LLC, and Alphabet Inc., the sole stockholder of XXVI Holdings Inc., may each be deemed to have sole power to vote or dispose of these shares. Each of GV 2016 GP, L.P., GV 2016 GP, L.L.C., Alphabet Holdings LLC, XXVI Holdings Inc. and Alphabet Inc. disclaim beneficial ownership of the shares except to the extent of any pecuniary interest therein.

F2 · ownership.nature: The reported securities are directly held by GV 2016, L.P. GV 2016 GP, L.P., the general partner of GV 2016, L.P., GV 2016 GP, L.L.C., the general partner of GV 2016 GP, L.P., Alphabet Holdings LLC, the sole member of GV 2016 GP, L.L.C., XXVI Holdings Inc., the managing member of Alphabet Holdings LLC, and Alphabet Inc., the sole stockholder of XXVI Holdings Inc., may each be deemed to have sole power to vote or dispose of these shares. Each of GV 2016 GP, L.P., GV 2016 GP, L.L.C., Alphabet Holdings LLC, XXVI Holdings Inc. and Alphabet Inc. disclaim beneficial ownership of the shares except to the extent of any pecuniary interest therein.